Method and apparatus for manufacturing slip stopper

ABSTRACT

An easy manufacturing method of a slip stopper, and apparatus therefor, that has a great slip stopping effect and can be used for a location where a problem occurs if a though hole is opened therein. After a protruding portion is formed on a steel plate, by using a first punching die unit, so as to protrude from the upper surface in a plate thickness direction, a concave portion and drain channels are formed in the protruding portion by shear planes that extend substantially perpendicular to the steel plate upper surface and have been half-blanked so as not to open a through hole in the steel plate by using a second punching die unit.

This application claims priority from JP2002-002651, filed Jan. 9, 2002through PCT/JP02/11741 filed Nov. 11, 2002. The disclosures of theidentified documents are enclosed herein by reference thereto.

BACKGROUND OF THE INVENTION

1. Technical Field

The invention relates to the technical fields of a method and anapparatus for manufacturing a slip stopper employed for a constructionmachine, such as a hydraulic excavator, or other surfaces that need tobe non-slip.

2. Background Art

Generally, a slip stopper with a slip stopping function is occasionallyused for floors, passageways, and stairs in building structures, floorsand steps of buses, trucks and special vehicles, decks of railroadvehicles and ships, and scaffolding at construction sites. Such a slipstopper, for example, as shown in FIGS. 10(A)–10(C), has beenconventionally known. This is a so-called striped steel plate that has aplurality of projections 51 molded in continuous patterned shape, and acorresponding slip stopping effect can be expected in the case of normalscaffolding. However, the height of the projections 51 of this stripedsteel plate is low and curved, so that a more reliable slip stopper isrequired when workers step on a cover covering the upper surface of aconstruction machine as a stepping surface during maintenance.

Therefore, as shown in FIGS. 11(A)–11(B), a slip stopper forconstruction machines has been provided in which slip stopping parts 53,having raised edges formed by the marginal portion of a through hole 52stamped out into a circle shape or a star shape, are formed in a runningpattern. In this slip stopper, the raised portions of the slip stoppingpart 53 can be made sufficiently high, and sharp shear planes are formedby means of the stamping-out process, so that a great slip stoppingeffect can be obtained.

If the slip stopper having the through hole stamped out is used as it isas a cover to cover the upper surface of a construction machine,problems, such as rainwater or dirt entering the inside of the cover,heated air from an engine blowing upward from the cover, or noisediffusing, are inevitable. Therefore, a double structure in that a flatsteel plate is fixed to the lower side of the slip stopper is employedto prevent the abovementioned problems. However, the double structureincreases production processes and costs in comparison with the singlestructure and, further, poses a problem in that mud or dust enteringthrough the through hole of the slip stopper accumulates between theslip stopper and the lower side flat steel plate or in the through hole,and makes cleaning difficult. These problems are solved by theinvention.

SUMMARY OF THE INVENTION

In view of the abovementioned circumstances, the invention has beendeveloped to solve the abovementioned problems, wherein after aprotruding portion is formed on a plate surface of a metal plate so asto protrude in the plate thickness direction, a concave portion isformed in the protruding portion by shear planes which extend almostperpendicularly to the plate surface of the metal plate and are obtainedby half blanking that does not open a through hole in the metal plate.

Thereby, a slip stopper which achieves a great slip stopping effect andcan be used for a location where a problem occurs if a through hole isopened therein can be easily manufactured.

Furthermore, the invention comprises a first punching die unit forforming a protruding portion on a plate surface of a metal plate so asto protrude in the plate thickness direction, a second punching die unitfor forming a concave portion by shear planes which extend almostperpendicularly to the plate surface of the metal plate and are obtainedby half blanking that does not open a through hole in the metal plate.

By using the first and second punching die units, a slip stopper whichachieves a great slip stopping effect and can be used for a locationwhere a problem occurs if a through hole is opened therein can be easilymanufactured.

The invention can be widely applied in the technical fields of a methodand an apparatus for manufacturing a slip stopper for various footingsrequiring a device to prevent slipping, such as the stepping surfaces ofconstruction machines, floors, passageways, and stairs of buildingstructures, floors and steps of buses, trucks, and special vehicles,decks of railroad vehicles and ships, scaffolding at construction sites,etc. The invention can also be used for a location where a problemoccurs if a through hole is opened therein, and is useful in a casewhere it is necessary to readily manufacture a slip stopper having agreat slip stopping effect at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS

The method and apparatus will be described with reference to thedrawings, in which:

FIG. 1 is a plan view of a construction machine;

FIG. 2 is a partial plan view of a slip stopper;

FIG. 3(A) is a plan view of a slip stopping part, FIG. 3(B) is an 3B—3Bsectional view of FIG. 3(A), and FIG. 3(C) is a 3C–3C sectional view ofFIG. 3(A);

FIG. 4(A) is a perspective plan view of a slip stopping part, and FIG.4(B) is a perspective bottom view of the slip stopping part;

FIG. 5 is a sectional view of a first punching die unit when a strikermoves up;

FIG. 6 is a sectional view of the first punching die unit when thestriker moves down;

FIG. 7(A) is a plan view of a protruding portion after a first processis finished, and FIG. 7(B) is a 7B–7B sectional view of FIG. 7(A);

FIG. 8 is a sectional view of a second punching die unit when a strikermoves up;

FIG. 9 is a sectional view of the second punching die unit when thestriker moves down;

FIG. 10(A) is a plan view of a checkered steel plate, FIG. 10(B) is a10B–10B sectional view of FIG. 10(A), and FIG. 10(C) is a 10C—10Csectional view of FIG. 10(A); and

FIG. 11(A) is a plan view of a slip stopping part in which a throughhole is opened, and FIG. 11(B) is an 11B—11B sectional view of FIG.11(A).

DETAILED DESCRIPTION

In the drawings, a construction machine (hydraulic excavator) 1 isconstructed so that the upper surfaces of a cover 2 covering the uppersurface of the construction machine body and a tool box 3 are formed asstepping surfaces on which a worker walks and steps during maintenance,and a slip stopper 4 to which the invention has been applied is used onthese stepping surfaces.

The slip stopper 4 (FIGS. 2–3(C)) has a plurality of slip stopping parts6 formed in a vertically and horizontally running pattern on a flatsteel plate 5. In the slip stopping parts 6, a concave portion 8 anddrain channels 9 are formed in a protruding portion 7, that protrudes inthe plate thickness direction from the upper surface 5 a of the steelplate 5, by shear planes 8 a, 9 a described later.

Namely, the protruding portion 7 is circular in a plan view and has aroughly arc-shaped section. A roughly quadrilateral concave portion 8 isformed at the central portion of the upper surface side of thisprotruding portion 7, and the level of the bottom portion of thisconcave portion 8 is designed so as to be higher than the upper surface5 a of the steel plate 5. Furthermore, four drain channels 9, that areshaped into concave grooves leading to the upper surface 5 a of thesteel plate 5 from the concave portion 8, are formed radially, and thegroove bottom portions of the drain channels 9 are formed to be inclinedfrom the level which is almost equal to the level of the upper surfaceof the concave portion 8 at the concave portion 8 side, to become almostequal to the level of the upper surface of the protruding portion 7 atthe marginal section of the protruding portion 7 and the upper surfacesof the steel plate 5, i.e., are highest at the concave portion 8 sideand lower toward the marginal side of the protruding portion, wherebywater or dirt is prevented from accumulating in the concave portion 8.On the other hand, at the lower surface side of the protruding portion7, portions 8 b, 9 b that are the back surface sides of the concaveportion 8 and the drain channels 9 protrude downward.

Herein, the inner circumferential surface of the concave portion 8 andthe groove side surfaces of the drain channels 9 are formed by shearplanes 8 a, 9 a which extend substantially perpendicular to the uppersurface 5 a of the steel plate 5 and have been half-blanked so as not toopen a through hole in the steel plate 5. Furthermore, the shear planes8 a, 9 a are sheared so that the upper edges are shaped acutely, thatis, acute edges are raised.

To form the slip stopping part 6, after a first process in which aprotruding portion 7 is formed using first and second punching die units10, 11, a second process is carried out in which the concave portion 8and the drain channels 9 are formed.

Namely, the first punching die unit 10 is for forming the protrudingportion 7 on the steel plate 5, and comprises a punch assembly 12, a dieassembly 13, and a striker 14. The punch assembly 12 comprises a punch16 for forming a protruding portion, to be fitted in a guide hole 15 aopened in an upper base 15 in a manner enabling it to move up and down,a flange 18 integrally attached to the upper end of the punch 16 via abolt 17, a punch head 20 integrally attached to the upper side of theflange 18 via a bored bolt 19, a support member 22 which is supported bya guide bolt 21 fixed to the upper base 15 in a manner enabling it tomove up and down, and comes into contact with the flange 18 from below,and a spring 23 which presses the support member 22 upward, etc. The dieassembly 13 comprises a die 25 for forming a protruding portion, fixedto a lower base 24, a stripper bolt 26 which is fastened to the die 25with the head downward, a urethane spring 27 through which the stripperbolt 26 is inserted, upper and lower collars 28, 29 through which thestripper bolt 26 is inserted while the collars are positioned at theupper side and the lower side, and an ejector plate 31 which is fixed tothe upper collar 28 via an ejector bolt 54 and guided to the die 25 viaa stopper bolt 30 in a manner enabling it to move up and down for apredetermined distance.

In the first punching die unit 10, while the striker 14 moves up, asshown in FIG. 5, the punch 16 is positioned at a moved-up positionseparated from the die 25, i.e., withdrawn inside the guide hole 15 a ofthe upper base 15 because the support member 22 that has been retainedat a predetermined position by the pressing force of the spring 23 is incontact with the flange 18 from below. Further, the ejector plate 31 ispositioned by the pressing force of the urethane spring 27 so that theupper end of the ejector plate 31 is at almost the same height as theupper end of the die 25.

When the striker 14 is moved down, after the steel plate 5 is setbetween the punch 16 and the die 25 in a condition where the striker 14is moved up, as shown in FIG. 6, the punch 16 moves down to project fromthe guide hole 15 a, and a protruding portion 7 is formed on the steelplate 5 by being pressed by the punch 16 that has moved down and the die25. At this point, the ejector plate 31 is moved down by being pressedby the punch 16 via the steel plate 5. Thereafter, in accordance withthe moving-up of the punch 16 after forming the protruding portion 7,the ejector plate 31 is moved up by the pressing force of the urethanespring 27 to separate the steel plate 5 from the die 25.

The second punching die unit 11 is for forming the concave portion 8 andthe drain channels 9 in the protruding portion 7 formed by the firstpunching die unit 10. The second punching die unit 11 comprises, as inthe case of the abovementioned first punching die unit 10, a punchassembly 32, a die assembly 33, and a striker 34. The punch assembly 32of the second punching die unit 11 comprises a punch guide 36 which isfitted in a guide hole 35 a opened in an upper base 35 in a mannerenabling it to move up and down, a flange part 36 b which is integrallyformed at the upper end of the punch guide 36, a stripper plate 38 whichis fastened to the lower end of the punch guide 36 via a stopper bolt37, a punch 39 for forming a concave portion and drain channels, to beinserted through the cylindrical hole portions 36 a, 38 a opened in thepunch guide 36 and the stripper plate 38 in a manner enabling it to moveup and down so that the upper end projects upward from the flange part36 b, and a stripping spring 40 interposed between the upper end of thepunch 39 and the flange part 36 b, a support member 42, which is guidedby a guide bolt 41 fixed to the upper base 35, in a manner enabling thesupport member 42 to move up and down, and comes into contact with theflange part 36 b from below, and a spring 43 which presses the supportmember 42 upward, etc. The die assembly 33 comprises a die 45 forforming a concave portion and drain channels, fixed to the lower base44, a stripper bolt 46 that is the same as in the first punching dieunit 10, a urethane spring 47, upper and lower collars 48, 49, and anejector plate 50, etc.

When the striker 34 moves up, in the second punching die unit 11, asshown in FIG. 8, the support member 42 is retained at a predeterminedposition by the pressing force of the spring 43 which is in contact withthe flange part 36 b from below. The punch guide 36 is positioned at amoved-up position separated from the die 45 so that the stripper plate38 is withdrawn inside the guide hole 35 a opened in the upper base 35.The punch 39 withdraws into the cylindrical hole portion 38 a of thestripper plate 38 due to the pressing force of the stripping spring 40.Furthermore, the ejector plate 50 is positioned, by the pressing forceof the urethane spring 47, so that the upper surface of the ejectorplate 50 is at nearly the same height as that of the upper end of thedie 45.

When the striker 34 is moved down, after the protruding portion 7 of thesteel plate 5 is positioned between the punch 39 and the die 45 in acondition where the striker 34 is moved up, the punch 39 and the punchguide 36 move down together first, and accordingly, the stripper plate38 projects downward from the guide hole 35 a of the upper base 35 andthe stripper plate 38 comes into contact with the upper surface 5 a ofthe steel plate 5, whereby the steel plate upper surface 5 a is pressedby the stripper plate 38. Next, the punch 39 moves down alone and thepunch 39 that has moved down and the die 45 form the concave portion 8and the drain channels 9 in the protruding portion 7. The innercircumferential surface of the concave portion 8 and the groove sidesurfaces of the drain channels 9 are formed by, as mentioned above,shear planes 8 a, 9 a that are substantially perpendicular to the uppersurface 5 a of the steel plate 5 and have been half-blanked so as not toopen a through hole in the steel plate 5. In this case, by setting theclearance between the punch 39 and the die 45 edges to zero, acute edgescan be formed at the upper edges of the shear plates 8 a, 9 a.

Further, when the punch 39 moves upwardly after the concave portion 8and drain channels 9 are formed, the stripper plate 38 and the ejectorplate 50 act to separate the steel plate 5 from the punch 39 and the die45 as in the same manner as the ejector 31 of the first punching dieunit 10 mentioned above.

In this embodiment, the first and second punching die units 10, 11 areattached to the turret of a turret punch press (not shown). The steelplate 5 is supported on the table of the turret punch press, and thesecond process for forming the concave portion 8 and the drain channels9 is carried out successively from the first process by moving eitherthe turret or the table for positioning of the punching die unitsrelative to the steel plate 5.

In the abovementioned structure, at each slip stopping part 6, a concaveportion 8 is formed at the central portion of the protruding portion 7that protrudes in the plate thickness direction from the upper surfaceof the steel plate 5. Drain channels 9, shaped into concave grooves, areformed radially from the concave portion 8 so as to lead to the uppersurface 5 a of the steel plate 5. The concave portion 8 and drainchannels 9 are formed by shear planes 8 a, 9 a that extend substantiallyperpendicular to the upper surface 5 a of the steel plate 5 and havebeen half-blanked so as not to open a through hole in the steel plate 5.The shear planes 8 a, 9 a can achieve an excellent reliable slipstopping effect because their protrusions project from the steel plateupper surface 5 a according to the protrusion height of the protrudingportion 7, and the upper edges are acute. In this embodiment, the anglesbetween each shear plane 8 a and the upper surface of a protrudingportion 7 and between each shear plane 9 a and the upper surface of theprotruding portion 7 becomes smaller to become a more acute angle as theinclination of the protruding portion 7 increases. Because as theseangles become smaller to be a more acute angle more acute edges can beraised at the upper edges of the shear planes 8 a, 9 a, the slipstopping effect can be further improved.

In this structure because the shear planes 8 a, 9 a have beenhalf-blanked so as not to open a through hole in the steel plate 5,problems, such as water or dirt entering inside the cover 2 or the toolbox 3, the blowing up of heated air from an engine, and noise diffusionto the outside, can be prevented without the conventional doublestructure with a through hole opened, resulting in a significant costreduction.

Further, in this structure because the drain channels 9 are formed to beinclined, the slip stopping effect is not lost by the accumulation ofwater or dirt in the concave portion 8, cleaning can be easily carriedout even if dirt or dust accumulates in the concave portion 8 or thedrain channels 9, and, as the groove side surfaces of the drain channels9 are formed by shear planes 9 a, the abovementioned slip stoppingeffect is further increased.

Thus, the slip stopping part 6 has a great slip stopping effect and doesnot open a through hole in the steel plate 5. To form this slip stoppingpart 6, the second process for forming the concave portion 8 and thedrain channels 9 by the second punching die unit 11 is carried out afterthe first process for forming the protruding portion 7 by the firstpunching die unit 10.

As a result, the protruding portion 7 can be formed to be sufficientlyhigh above the surface 5 a of the steel plate 5, the stress to beapplied to the steel plate 5 when shearing the protruding portion 7 bymeans of half blanking can be reduced, and acute edges can be raised atthe upper edges of the shear planes 8 a, 9 a, whereby an excellent slipstopping effect can be achieved as mentioned above.

1. A method for manufacturing a slip stopper, comprising: forming aplurality of protruding portions on a metal plate so as to protrude inthe plate thickness direction; and forming concave portions in theprotruding portions defined by shear planes that extend substantiallyperpendicular to the plate surface of the metal plate to form a slipstopper and have been half-blanked from a protruding surface side of theprotruding portions so as not to open through holes in the metal plate.2. The method according to claim 1, further comprising: placing themetal plate between a punching assembly and a die assembly of a firstpunching die unit prior to forming the plurality of protruding portions;and relatively moving the metal plate relative to the first punching dieunit and a second punching die unit after forming the plurality ofprotruding portions, to place the metal plate between a punch assemblyand a die assembly of the second punching die unit.
 3. The methodaccording to claim 1, wherein the concave portions comprise a centralconcave portion and radial drain channels.
 4. The method according toclaim 3, wherein the central concave portion is depressed from an uppersurface of the protruding portion and each drain channel has an uppersurface at one end extending from an upper surface of the centralconcave portion and at the other end joining the plate surface of themetal plate.
 5. An apparatus for manufacturing a slip stopper,comprising: a first punching die unit that forms a plurality ofprotruding portions on the surface of a metal plate so as to protrude inthe plate thickness direction; and a second punching die unit that formsconcave portions respectively in the protruding portions formed by thefirst punching die unit by creating shear planes that extendsubstantially perpendicular to the plate surface of the metal plate toform a slip stopper and have been half-blanked from a protruding surfaceside of the protruding portions so as not to open through holes in themetal plate.
 6. The apparatus according to claim 5, wherein the firstpunching die unit comprises: a punch assembly having a punch with aconcave face, a punch head, a punch body slideably holding the punch,and a retractor that biases the punch into a retracted position withinthe punch body; a die assembly including a die having a convex face tooppose the concave face of the punch, a die body mounting the die, anejector plate slideably mounted in the die body relative to the die; anda pushing member that pushes the ejector plate toward the punch body;and a striker.
 7. The apparatus according to claim 6, wherein the secondpunching die unit comprises: a punch assembly having a punch with aconcave face having a central projection and radial projections, theradial projections having a decreasing height of projection from thecentral projection to no projection at the edge of the concave face, apunch body receiving the punch for reciprocal movement, a stripper plateslideably received on the punch adjacent the concave face, a firstretractor that biases the punch into a retracted position within thepunch body, and a second retractor that retracts the stripper platewithin the punch body; a die assembly comprising a die body, a diemounted in the die body and having a convex face substantiallycomplementary to the concave face of the punch, an ejector plateslideably mounted in the die body relative to the die, and a pushingmember that pushes the ejector plate toward the punch body; and astriker.
 8. The apparatus according to claim 7, wherein the pushingmember in each of the first punching die unit and the second punchingdie unit is a urethane spring.
 9. The apparatus according to claim 7,wherein the retractor in each of the first punching die unit and thesecond punching die unit is a spring.
 10. The apparatus according toclaim 7, wherein the punch assembly of the first punching die unitfurther comprises a flange between the punch head and the punch, thepunch head, flange and punch being assembled into a unitary structure.11. The apparatus according to claim 5, wherein the second punching dieunit comprises: a punch assembly having a punch with a concave facehaving a central projection and radial projections, the radialprojections having a decreasing height of projection from the centralprojection to no projection at the edge of the concave face, a punchbody receiving the punch for reciprocal movement, a stripper plateslideably received on the punch adjacent the concave face, a firstretractor that biases the punch into a retracted position within thepunch body, and a second retractor that retracts the stripper platewithin the punch body; a die assembly comprising a die body, a diemounted in the die body and having a convex face substantiallycomplementary to the concave face of the punch, an ejector plateslideably mounted in the die body relative to the die, and a pushingmember that pushes the ejector plate toward the punch body; and astriker.
 12. The apparatus according to claim 11, wherein the firstpunching die unit comprises: a punch assembly having a punch with aconcave face, a punch head, a punch body slideably holding the punch,and a retractor that biases the punch into a retracted position withinthe punch body; a die assembly including a die having a convex face tooppose the concave face of the punch, a die body mounting the die, anejector plate slideably mounted in the die body relative to the die; anda pushing member that pushes the ejector plate toward the punch body;and a striker.
 13. The apparatus according to claim 12, wherein thepushing member in each of the first punching die unit and the secondpunching die unit is a urethane spring.
 14. The apparatus according toclaim 12, wherein the retractor in each of the first punching die unitand the second punching die unit is a spring.
 15. The apparatusaccording to claim 12, wherein the punch assembly of the first punchingdie unit further comprises a flange between the punch head and thepunch, the punch head, flange and punch being assembled into a unitarystructure.